APC PowerStack 250/450
Uninterruptible Power Supply User’s Manual
990-5017 Revision 1 7/98
To obtain warranty coverage, please fill out and
return the warranty registration card now.
Inspect the APC PowerStack 250/450
Uninterruptible Power Supply (UPS) upon receipt.
Notify the carrier and dealer if there is damage. The
packaging is recyclable; save it for reuse or dispose
of it properly.
Battery Connection
Before beginning installation of the UPS, please
follow the Battery Connection instructions on the
front of the unit, or follow the steps under Replacing
the Battery Pack.
Wall Mounting
The brackets on the UPS can be rotated 90 ° for wall
mounting. Remove the screws, rotate the brackets,
and insert the screws in the appropriate holes.
Wall-mount the unit
with the controls
towards or at the
top, not at the
bottom of the unit .
Desktop Use
This UPS is provided with four adhesive-backed
rubber “feet” for desktop use. Attach the feet to the
bottom of the unit and remove the ears to use it on a
The recommended placement of the feet is shown by
a small + on the bottom corners of the unit:
The illustrations above show the proper positions for
wall mounting the unit
Warning! Changes or modifications to this unit
not expressly approved by the party responsible
for compliance could void the warranty.
Do not mount the unit
on the wall as shown
in the illustrations at
left. Doing so could
result in a safety
Rack Mounting
The UPS comes with standard 19" (46.5 cm) rack
mount brackets. It is supplied with four (4) screws
to attach the mounting brackets (ears) to the chassis.
Select a rack location with adequate air flow that is
free from excessive dust. Ensure that the air vents on
the sides of the UPS are not blocked. Do not operate
the UPS where temperature or humidity are outside
the limits in the Specifications section of this
Rear View
Once the UPS is mounted, please follow the
installation instructions in the Smart-UPS Quick
Reference Guide.
Check the Site Wiring Fault Indicator
Caution! If the site wiring fault indicator lights,
get a qualified electrician to correct the building
Computer Interface Port
The interface port is used for communicating with
the UPS. See enclosed documentation for details.
Connect the Battery Pack
The UPS is shipped with the battery pack
disconnected. To connect the battery pack, follow
the procedure in Replacing the Battery Pack, below.
Charge the battery pack
The UPS charges its battery pack whenever it is
connected to utility power. The battery pack will
charge fully during the first 4 hours of normal
operation. Do not expect full battery back-up
runtime during this initial charge period.
Operating Instructions
Switch On — Switch Off
With the UPS plugged in, press and release the
on/off/test button to supply power to the loads.
The loads are immediately powered while the UPS
performs a self-test. Press and release the button
again to turn off power to the loads. It may be
convenient to use the UPS as a master on/off switch
for the protected equipment.
The green on-line LED illuminates when the
UPS is supplying utility power to the loads.
The UPS performs a self-test automatically when
turned on, and every two weeks thereafter.
Automatic self-test eases maintenance requirements
by eliminating the need for periodic manual selftests.
On Battery
During on-battery operation, the yellow on-battery
LED illuminates and the UPS sounds an audible
alarm consisting of 4 beeps every 30 seconds. The
alarm stops when the UPS returns to on-line
Low Battery
When the UPS is operating on-battery and the
energy reserve of the battery pack runs low, the UPS
beeps continuously until the UPS shuts down from
battery pack exhaustion or returns to on-line
operation, if the utility power returns before the
battery pack is exhausted..
Replace Battery
If the battery pack fails a self-test, the UPS emits
short beeps for one minute and the red replace
battery LED illuminates.
The UPS repeats the alarm every five hours. Perform
the self-test procedure to confirm replace battery
conditions. The alarm stops when the battery pack
passes the self-test.
During the self-test, the UPS briefly powers the loads
on-battery. If the UPS passes the self-test, it returns
to on-line operation.
Cold Start
Note: Cold start is not a normal operating
When the UPS is off and there is no utility power, it
is possible to cold start the UPS to power the loads
from the UPS’s battery pack.
Press and hold the on/off/test button until the
UPS emits a constant tone.
· Release the on/off/test button during the tone to
start the UPS.
When loads exceed the UPS’s capacity, the red
overload LED illuminates and the UPS emits a
sustained tone. The alarm remains on until the
overload is removed. Disconnect nonessential load
equipment from the UPS to eliminate the overload.
If the overload is severe, the input circuit breaker
may trip (the resettable center plunger of the circuit
breaker pops out). Disconnect nonessential load
equipment from the UPS to eliminate the overload
and press the plunger back in.
If there is AC power and the circuit breaker does not
trip during overload, the loads are still powered. If
the circuit breaker trips or the UPS attempts to
transfer to battery, the loads’power will be shut off.
Turn the UPS off then back on to power the loads.
If the UPS turns off during the self-test and emits a
fading tone, the batteries are not connected properly.
The loads are not affected by a failed test. Recharge
the battery pack overnight and perform the self-test
again. If the replace battery LED is still on, replace
the battery pack using the Replacing the Battery
Pack procedure.
Storage Conditions
Before storing, charge the UPS for at least 8 hours. Cover the UPS and store it lying
flat in a cool, dry location, with its battery pack fully charged.
Extended Storage
At -15 to +30 °C (+5 to +86 °F), charge the UPS’s battery pack every 6 months.
At +30 to +45 °C (+86 to +113 °F), charge the UPS’s battery pack every 3 months.
Replacing the Battery Pack
This UPS has an easy to replace hot-swappable battery pack.
Note: Please read the cautions in the APC Safety Guide.
1.Reach into the finger pull and remove the front cover.
2.Use a flat-blade screwdriver to turn the two battery door screws
¼ turn counterclockwise; open the door.
3.Grasp the clear plastic tab and gently pull the battery pack out
of the UPS until the battery connector is visible.
Warning! Do not force the battery pack out. This may
damage internal wiring!
Replacement Batteries
See your dealer or call the number in this manual for information on replacement
battery pack kits. For 250 models, order RBC17. For 450 models, order RBC18.
Battery Pack Replacement Procedure
Battery pack replacement is a safe procedure, isolated from electrical hazards. You
may leave the UPS and loads on for the following procedure.
4.Disconnect the battery connector by gripping both sides of the
connector and firmly pulling them apart.
Once the battery pack is disconnected, the loads are not protected from
power outages.
Be careful removing the batteries - they are heavy.
Small sparks at the battery connectors are normal during connection.
5.Slide the battery pack out of the UPS.
6.Slide the new battery pack three-fourths of the way into the
7.Connect the battery connector attached to the unit to the
connector attached to the new battery pack.
8.Push the battery pack in as far as it will go. There are stops in
the back to prevent it from going too far.
9.Close the battery door, turn the battery compartment screws ¼
turn clockwise, and replace the front cover.
10.Dispose of the old battery pack properly at an appropriate
recycling facility or return it to the supplier in the packing
material for the new battery pack. See the new battery pack
instructions for more information.
250 VA
450 VA
0 - 160 VAC
81-143 VAC
106-127 VAC
Resettable circuit breaker
47 - 63 Hz
4 ms typical, blackout response time
250 VA 165 W
450 VA 280 W
115 VAC
60 Hz, ±0.1 Hz; unless synchronized to utility
during brownout
Stepped sine-wave
Overcurrent and short-circuit protected, latching
shutdown on overload
Spill proof, maintenance free, sealed lead-acid
3 to 6 years, depending on number of discharge
cycles and ambient temperature
4 to 8 hours from total discharge
0 to +40 °C (+32 to +104 °F)
-15 to +45 °C (+5 to +113 °F)
5 to 95%, non-condensing
0 to +3,000 m (0 to +10,000 ft)
0 to +15,000 m (0 to +50,000 ft)
<38 dBA
1.75 x 17.5 x 13.0 in.
18.5 (23) lbs
21.5 (26) lbs
UL1778, CSA 107.1
FCC Part 15 Class A, VCCI Class A
EN 50082-1
IEC 1000-4-3
EN 61000-4-4
EN 61000-4-2
Acceptable input voltage
Input voltage (on-line operation)
Output voltage
Input Over Current Protection
Frequency limits (on-line operation)
Transfer time
Maximum load
On-battery output voltage
On-battery frequency
On-battery waveshape
Output Over Current Protection
Battery type
Typical battery life
Typical recharge time
Operating temperature
Storage temperature
Operating and storage relative humidity
Operating elevation
Storage elevation
Audible noise at 1 m (3 ft)
Size (H x W x D)
Weight - net (shipping)
Safety and approvals
EMC Emissions
EMC Immunity
LEDs and Audible Alarms
UPS is on
UPS is running on battery
UPS is performing self-test
Overload shutdown
Output short circuit
Transformer failure
Low Battery (while on battery)
Replace battery condition
Battery disconnected in self test
UPS internal alarms:
boost/trim failure
transfer relay weld
Sleep Mode
— = irrelevant to condition
m = on steady
X = flashing
l = Off
1 = sustained tone
2 = 1 minute of beeping every 5 hours
3 = fading tone
4 = 4 beeps every 30 seconds
If the UPS requires service do not return it to the dealer! Follow these steps:
1.Use the Troubleshooting section of the Quick Reference Guide to eliminate
common problems.
2.Verify that no circuit breakers are tripped. A tripped circuit breaker is the most
common UPS problem!
3.If the problem persists, call customer service or visit the APC Internet Website
4.Note the model number of the UPS, the serial number, and the date purchased. A
technician will ask you to describe the problem and try to solve it over the phone,
if possible. If this is not possible the technician will issue a Return Merchandise
Authorization Number (RMA#).
5.If the UPS is under warranty, repairs are free. If not, there is a repair charge.
6.Disconnect the batteries before packing the UPS.
7.Pack the UPS in its original packaging. If the original packing is not available,
ask customer service about obtaining a new set.
8.Pack the UPS properly to avoid damage in transit. Never use Styrofoam beads for
packaging. Damage sustained in transit is not covered under warranty.
9.Include a letter with your name, RMA#, address, copy of the sales receipt,
description of the trouble, your daytime phone number, and a check (if necessary).
10.Mark the RMA# on the outside of the package.
11.Return the UPS by insured, prepaid carrier to the address given to you by
Customer Service.
North & Latin America
132 Fairgrounds Road
West Kingston, Rhode Island 02892
Ballybritt Business Park
Galway, Ireland 1800-702000
Toll-free within the Republic
of Ireland only
Internet: http://www.apcc.com
North America: apctech@apcc.com
Europe: apceurtech@apcc.com
Latin America: apctchla@apcc.com